Quite agree guys that its not as we hoped it would be but, all that can be done within the restraints that are in place - IS being done.
Don't think it isn't happening to anyone else, either - not an excuse but, I get this 30/40 times a day and factor in having to trawl through posts I don't find particularly interesting - it does not make for a fun time!
Please hang in there, hopefully a resolution is close.
Sounds like a PHP resource leak. A temporary fix would be sessions configured to time-out sooner rather than trying to recycle existing sessions open that aren't in use. We've seen a lot of code using JRUN on Win32 and Python (PHP) - on Freebsd and Redhat that have been waiting too long for the Ack back from a client (that never turns up) - resulting in time-out ..... waiting and ... waiting until ... bam ! No more resources availbable for more sessions available.